JP2004304997A - Stator and brush-less motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator and a brush-less motor for reducing noise and vibration while attaining high output. <P>SOLUTION: The stator 30 comprises an outer core 30a of cylindrical shape and an inner core 30b formed by stacking an inner core sheet 34 comprising a plurality of iron core parts 35 provided in an internal peripheral side of the outer core 30a to radially protrude toward a radial direction inner side to install a winding 38, and a bridging part 36 link connecting the end part in an radial direction inner side of a plurality of iron core parts 35a to 35i with each other. A plurality of the bridging parts 36 formed in the inner core sheet 34 are formed with thin wall parts 37a to 37i having a prescribed width in a circumferential direction of the stator 30 with a thickness axially along the stator 30 formed thinner than the other part of the inner core sheet 34. At least one circumferential direction width of the thin wall parts is formed so as to be different from the other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stator and a brushless motor, and more particularly to a stator and a brushless motor having a structure for reducing noise and vibration generated during operation.

  A rotating magnetic field type electric motor such as a brushless motor generates a rotating magnetic field by sequentially passing a current through windings wound around a plurality of iron cores of a stator, and generates a rotating magnetic field by using a magnet or a winding disposed on a rotor. The rotor is rotated by an interaction between the magnetic field and the rotating magnetic field. In the case of the inner rotor type electric motor, the iron core portion of the stator is radially arranged radially outside of the rotor, and the winding is wound around the iron core serving as the winding shaft of the winding. I have.

The stator is formed by laminating a core sheet of a predetermined shape made of a thin magnetic material such as a silicon steel plate in the rotation axis direction of the electric motor. In such a stator, a pillar-shaped inner core including a plurality of iron cores arranged radially outside the rotor and a bridging part connecting the radially inner ends of the plurality of iron cores to each other is provided. A cylindrical outer core for connecting and fixing the radially outer ends of the iron core portion of the inner core to each other, and laminating core sheets of a predetermined shape, and fixing the inner core and the outer core. Some are formed by the above.
By combining the cores thus divided to form the stator, the inner core sheets are laminated to form the inner core, and then the winding is easily formed on the iron core extending radially outward. Since it can be wound, workability for winding the winding around the iron core is ensured. Then, the stator can be formed by fixing the outer core formed by laminating the outer core sheet to the inner core on which the winding is wound.

However, in the stator configured as described above, since the iron core portion is linked by the bridge portion, a part of the magnetic flux generated from the magnet of the rotor flows in the bridge portion and becomes a leakage magnetic flux. This leakage magnetic flux does not act on the rotation of the rotor, which hinders miniaturization and high output of the electric motor.
To compensate for such inconvenience, a part of the bridge portion of the stator is formed to be thinner in the axial direction than the thickness of the core sheet to reduce the effective cross-sectional area and increase the magnetic resistance, thereby reducing the leakage flux. There is a configuration that prevents such a situation (for example, see Patent Document 1).
With this configuration, the magnetic flux hardly leaks through the bridging portion, so that the ineffective magnetic flux that does not contribute to rotation can be effectively reduced, and it is possible to increase the output and reduce the size of the motor. It becomes.

JP-A-9-19089 (pages 3 to 5, FIGS. 1 to 5)

  However, in the electric motor having the above-described structure, by forming the bridge portion thin, it is possible to reduce the leakage magnetic flux and achieve high output, but on the other hand, by forming the bridge portion thin, the rotational torque generated in the motor is reduced. Cogging torque (pulsation torque) increases. Further, since the cogging torque generates noise and vibration in the electric motor, there is a problem that noise countermeasures are not sufficient.

  An object of the present invention is to provide a stator and a brushless motor capable of achieving high output and reducing noise and vibration in view of the above problem.

  According to the stator according to claim 1, the object is to provide a cylindrical outer core, and a plurality of iron cores provided on the inner peripheral side of the outer core and projecting radially inward and wound with windings. And an inner core formed by laminating inner core sheets each including a radially inner end of each of the plurality of iron cores. The plurality of bridge portions formed on the inner core sheet have a predetermined width in the circumferential direction of the stator and have a thickness along the axial direction of the stator that is smaller than other portions of the inner core sheet. The problem is solved by forming the thin portions and forming at least one of the thin portions in the circumferential direction to be different from the other.

Thus, the stator of the present invention includes the inner core formed by laminating the outer core and the inner core sheet, and the inner core sheet includes a plurality of radially arranged iron cores and a radially inner side of the iron core adjacent to the core. A bridging part that connects the ends to each other is provided. In each of the bridge portions, a thin portion having a predetermined width in the circumferential direction and being thinner than other portions of the inner core sheet is formed.
By forming in this manner, the cross-sectional area of the bridging portion is reduced and the magnetic resistance of the bridging portion is increased, so that the magnetic flux received from the magnet rotor arranged inside the stator becomes difficult to pass through the bridging portion, It is possible to reduce the leakage magnetic flux that does not contribute to the rotation of the motor, increase the effective magnetic flux, and increase the output of the motor.

  Further, in the present invention, the circumferential widths of the thin portions formed in the plurality of bridge portions are formed to be unequal so as not to be the same. As a result, during the operation of the motor, the magnetic interaction between the magnetic flux of the rotor magnet and the bridging portion and the rotation angle at which the magnetic interaction occurs differ for each bridging portion. And noise and vibration of the motor due to cogging torque can be reduced as a whole.

Further, the inner core is formed by laminating each inner core sheet on which thin portions having different circumferential widths are formed. By making the circumferential widths of all the thin portions different in this way, it is possible to further reduce noise and vibration.
Further, the inner core may be formed by laminating each inner core sheet having a thin portion having a circumferential width different from each other so that circumferential widths of the thin portions adjacent in the axial direction are different from each other. Good. In this way, the effect of dispersing the frequency components in the axial direction can be expected, and noise and vibration can be suppressed.
Further, in each of the inner core sheets, the thin portions are formed so that their circumferential widths are different from each other, and the thin portions are formed such that the circumferential center thereof is circumferentially spaced from the circumferential center of the bridging portion. The inner core is formed such that the circumferential widths of the thin portions adjacent in the axial direction are substantially the same, and the displacement angles of the thin portions adjacent in the axial direction are substantially the same. As such, the inner core sheet may be formed by laminating the inner core sheets.
Further, in each of the inner core sheets, the thin portions are formed so that their circumferential widths are different from each other, and the thin portions are formed such that the circumferential center thereof is circumferentially spaced from the circumferential center of the bridging portion. The inner core is formed such that the circumferential widths of the thin portions adjacent to each other in the axial direction are different from each other, and the displacement angles of the thin portions adjacent to each other in the axial direction are substantially the same. Alternatively, the inner core sheet may be formed by laminating the inner core sheet.

  Further, as set forth in claim 2, a cylindrical outer core, a plurality of iron cores provided on the inner peripheral side of the outer core, projecting radially inward, and wound with windings, the plurality of iron cores, And an inner core formed by laminating inner core sheets each comprising a bridge portion connecting radially inner ends of the iron core portions to each other. Each of the formed bridge portions has a thin portion having a predetermined width in the circumferential direction of the stator and having a thickness along the axial direction of the stator thinner than other portions of the inner core sheet. Preferably, the thin portion is formed such that its circumferential center is shifted from the circumferential center of the bridging portion by a predetermined displacement angle in the circumferential direction.

As described above, according to the present invention, a thin portion having a predetermined width in the circumferential direction is formed in a bridging portion connecting the radially inner end portion of the iron core portion provided in the stator, and the plurality of thin portions are formed in the circumferential direction. Are formed with a predetermined displacement angle shifted from the center in the circumferential direction of the bridge portion.
With this configuration, the magnetic interaction between the magnetic flux of the rotor magnet and the bridging portion during the operation of the motor and the rotation angle at which the magnetic interaction occurs vary from bridge to bridging portion. The components are dispersed into a plurality of frequency components, so that noise and vibration of the motor due to cogging torque can be reduced as a whole.

Further, the inner core may be formed by laminating the inner core sheets such that displacement angles of the thin portions adjacent in the axial direction are different from each other. In this way, the effect of dispersing the frequency components in the axial direction can be expected, and noise and vibration can be suppressed.
Further, in each of the inner core sheets, the thin portion is formed so as to have substantially the same width in the circumferential direction, and the thin portions are formed so as to be shifted by substantially the same displacement angle. A plurality of types of inner core sheets set with different displacement angles of the thin portions may be formed by lamination such that the displacement angles of the thin portions adjacent to each other in the direction are different from each other.
At this time, the inner core can be formed by laminating the inner core sheets such that thin portions having substantially the same displacement angle are repeatedly arranged in the axial direction for each of a fixed number of the inner core sheets.
Furthermore, the inner core can be formed by alternately laminating two types of the inner core sheets set with different displacement angles of the thin portion.

Further, in each of the inner core sheets, the thin portion is formed so as to have substantially the same width in the circumferential direction, and in each of the inner core sheets, the thin portion adjacent in the circumferential direction has a magnitude of a displacement angle. May be substantially the same and the directions of displacement are opposite to each other, and the inner core may be formed by laminating the inner core sheets such that the displacement angles of the thin portions adjacent to each other in the axial direction are different from each other.
At this time, the inner core is configured such that a plurality of types of inner core sheets having different displacement angles of the thin portion are set in the axial direction for each of a fixed number of the inner core sheets having substantially the same displacement angle. May be formed so as to be repeatedly arranged.

Further, in each of the inner core sheets, the thin portions are formed so that their circumferential widths are different from each other, and the thin portions are formed so as to be shifted by substantially the same displacement angle, and the inner core is formed in the axial direction. A plurality of types of inner core sheets set so that the displacement angles of the thin portions are different from each other may be formed by laminating such that the displacement angles of the adjacent thin portions are different from each other.
At this time, the inner core can be formed by laminating the inner core sheets such that thin portions having substantially the same displacement angle are repeatedly arranged in the axial direction for each of a fixed number of the inner core sheets.
Furthermore, the inner core may be formed by laminating the inner core sheets such that the circumferential widths of the thin portions adjacent in the axial direction are substantially the same. Further, the inner core may be formed by laminating the inner core sheets so that circumferential widths of the thin portions adjacent in the axial direction are different from each other.

  Further, in each of the inner core sheets, the thin portion is formed so as to have substantially the same width in the circumferential direction, and the thin portions are formed so as to be shifted by substantially the same displacement angle. The widths in the circumferential direction and the displacement angles of the thin portions are set differently so that the circumferential widths of the thin portions adjacent in the direction are different from each other, and the displacement angles of the thin portions adjacent in the axial direction are different from each other. It may be formed by laminating a plurality of types of inner core sheets.

  Further, as set forth in claim 3, a cylindrical outer core, a plurality of iron cores provided on the inner peripheral side of the outer core, radially projecting radially inward, and wound with windings, And an inner core formed by laminating inner core sheets each comprising a bridge portion connecting radially inner ends of the iron core portions to each other. Each of the formed bridge portions has a thin portion having a predetermined width in the circumferential direction of the stator and having a thickness along the axial direction of the stator thinner than other portions of the inner core sheet. While being formed, at least one circumferential width of the thin portion is formed so as to be different from the other, and the thin portion has a circumferential center extending in a circumferential direction from a circumferential center of the bridging portion. Formed with a predetermined displacement angle It is preferred.

As described above, in the present invention, the thin portion formed in the bridging portion connecting the radially inner ends of the iron core portion has an uneven width in the circumferential direction, and has a center in the circumferential direction. Are formed at a predetermined displacement angle shifted from the center in the circumferential direction of the bridge portion.
Thus, in the present invention, the magnetic interaction between the magnetic flux of the rotor magnet and the bridge and the rotation angle at which the magnetic interaction is exerted can be made different for each bridge during the operation of the motor. The frequency component of the cogging torque is dispersed into a plurality of frequency components, so that noise and vibration of the motor due to the cogging torque can be reduced as a whole.
Further, the inner core may be formed by laminating inner core sheets on which thin portions having different circumferential widths are formed.

Further, as set forth in claim 4, a cylindrical outer core, a plurality of iron cores provided on the inner peripheral side of the outer core, projecting radially inward, and wound with windings, the plurality of iron cores, And an inner core formed by laminating inner core sheets each comprising a bridge portion connecting radially inner ends of the iron core portions to each other. The plurality of bridging portions are formed in a thin portion having substantially the same width in the circumferential direction of the stator and having a thickness along the axial direction of the stator thinner than other portions of the inner core sheet. Are formed, and the inner core is formed by laminating a plurality of types of inner core sheets having different circumferential widths of the thin portions so that the circumferential widths of the thin portions adjacent in the axial direction are different from each other. It is preferable to form .
As described above, according to the present invention, since the thin portions having substantially the same circumferential width are not arranged continuously in the axial direction, the magnetic flux of the rotor magnet and the magnetic The rotation angles that exert the interaction and the magnetic interaction can be different in the axial direction. As a result, the frequency component of the generated cogging torque is dispersed into a plurality of frequency components, and the noise and vibration of the motor due to the cogging torque can be reduced as a whole.

  In each of the inner core sheets, the thin portion is formed such that its circumferential center is shifted by a predetermined displacement angle in the circumferential direction from the circumferential center of the bridge portion, and the inner core is adjacent to the axial direction. The inner core sheets can be formed by laminating such that the displacement angles of the matching thin portions are substantially the same.

  Further, in the above stator, the plurality of iron cores may be formed at irregular intervals in a circumferential direction of the stator. In this way, if the iron cores are formed at irregular intervals in the circumferential direction of the stator, the center of the plurality of iron cores and the center of the rotor magnet are substantially matched during operation of the motor, and The phase shift of the induced voltage of the winding can be reduced, and the conversion loss when converting the exciting current supplied to the winding into the rotating magnetic field can be suppressed to a small value, so that the output of the motor can be increased. At the same time, noise and vibration during operation of the motor can be reduced, which is preferable.

Further, in the above stator, the inner core sheet may be formed such that the thin portion is formed by forming a concave portion on one side, the other side, or both sides of the bridge portion in the axial direction. .
At this time, the inner core forms a recess on one side in the axial direction of the bridging portion, thereby forming the inner core sheet on which the thin-walled portion is formed, and forming recesses on both axial sides of the bridging portion. The inner core sheet on which the thin portion is formed, and the inner core sheet on which the thin portion is formed by forming a concave portion on the other axial side of the bridging portion, are formed by laminating in this order. can do.
As described above, by forming the concave portion on any of the upper side, the lower side, and both sides, a thin portion can be formed, whereby the frequency component is dispersed, and noise and vibration are reduced.

Further, a brushless motor according to the present invention includes the above-described stator, and a rotor which is disposed inside the stator and has magnets of different polarities arranged alternately at substantially equal intervals in a circumferential direction of an outer peripheral surface. And
Since the brushless motor of the present invention includes the above-described stator, noise and vibration caused by cogging torque generated during operation can be reduced.

According to the stator and the brushless motor of the present invention, at least the circumferential width of the plurality of thin portions formed in the bridge portion connecting the radially inner side of the iron core portion of the stator for preventing magnetic flux leakage is constant in the circumferential direction. It is formed unevenly so as not to be formed, or formed at a position where each thin portion is displaced by a predetermined angle from the center portion of the bridging portion. Further, the thin portions having the same angular width are formed so as not to be continuous in the axial direction. Further, the thin portions having the same displacement angle amount are laminated so as not to be continuous in the axial direction.
With such a configuration, the frequency component of the pulsation of the cogging torque generated during the operation of the brushless motor is dispersed into a plurality of components, and a stator capable of increasing the output and reducing noise and vibration during the operation is provided. A brushless motor can be provided.

An embodiment of the present invention will be described with reference to the drawings, taking a brushless motor M as a rotating electric machine as an example. Further, the arrangement, shape, and the like described below do not limit the present invention, and it is needless to say that various modifications can be made in accordance with the gist of the present invention.
FIG. 1 is a sectional view of a brushless motor, FIGS. 2 to 8 relate to the brushless motor of the first embodiment, FIG. 2 is a sectional view of a stator and a rotor, FIG. 3 is a perspective view of a stator core, and FIG. FIGS. 5, 6, and 8 are development explanatory views of the stator of the first embodiment, and FIG. 6 is a development explanatory view of the inner core sheet.
9 and 10 relate to the brushless motor according to the second embodiment. FIG. 9 is a sectional view of a stator and a rotor, and FIG. 10 is a partially enlarged view of the stator. 11 and 12 relate to a brushless motor according to a third embodiment. FIG. 11 is a sectional view of a stator and a rotor, and FIG. 12 is a partially enlarged view of the stator.
FIGS. 13 to 22 are development explanatory views of the stators of the brushless motors of the fourth to thirteenth embodiments, respectively.

(Example 1)
Referring to FIG. 1, a configuration of an inner rotor type brushless motor M according to an embodiment of the present invention will be described. The brushless motor M includes a rotor 20 having a rotating shaft 22 attached thereto, bearings 41 and 42 rotatably supporting the rotor 20, and a three-phase exciting current (U-phase, V-phase , W-phase), a stator 30 on which windings 38 (windings 38U, 38V, 38W) are wound, and a housing 40 for housing these.
Although not shown, the brushless motor M is provided with a well-known position detector including a Hall element, a rectifying element, a position detecting magnet and the like, and a control circuit. Detection is performed. The control circuit supplies a current to each phase winding of the winding 38 based on the position signal and the speed set value obtained by the position detection, thereby generating a rotating magnetic field in the stator 30 and rotating the rotor 20 stably. can do.

FIG. 2 is a sectional view of the rotor 20 and the stator 30. The rotor 20 has a configuration in which a magnet 26 is arranged on the outer peripheral surface of a shaft 24 to which a rotating shaft 22 is attached. The magnet 26 is formed in a slightly curved plate shape, and is magnetized so that magnetic flux is directed in the plate thickness direction.
The rotor 20 of the present embodiment has eight magnetic poles, and two types of magnets 26 having different magnetic flux directions are alternately arranged on the outer peripheral surface of the rotor 20 at positions shifted by 45 degrees in rotation angle of the rotor 20. It has become.

  As shown in FIGS. 2 and 3, the stator 30 includes a stator core including an outer core 30a and an inner core 30b formed by laminating a thin plate-shaped outer core sheet 32 and an inner core sheet 34, respectively, and an iron core of the inner core 30b. And a winding 38 (winding 38U, winding 38V, winding 38W) wound around the portion 35 (iron core portions 35a to 35i). The outer core sheet 32 and the inner core sheet 34 are formed by pressing a magnetic material such as a silicon steel plate of the same thickness, which has been subjected to an insulating treatment such as an insulating film, into a predetermined shape.

The outer core sheet 32 is formed in a ring shape, and concave fitting portions 32a are formed radially inward at intervals of a central angle of approximately 40 degrees. The inner core sheet 34 includes nine iron core portions 35a to 35i (that is, the number of salient poles is nine) radially arranged at intervals of a central angle of approximately 40 degrees, and a radius of the adjacent iron core portion 35. And a bridging portion 36 that connects the ends on the inside in the direction. Further, a tab tail portion 34 a to be fitted to the fitting portion 32 a of the outer core sheet 32 is formed at the radially outer end of the iron core portion 35.
The bridging portion 36 is narrow in the radial direction, and integrally connects the plurality of iron core portions 35 to integrally support the iron core portions 35. At a substantially central portion in the circumferential direction of each bridging portion 36, a thin portion 37 having a predetermined angular width, which is thinner than other portions of the inner core sheet 34, is formed. The inner core sheet 34 is punched into a predetermined shape by press working, and the corresponding portion is pressed, so that the thin portion 37 is thinned to about half the thickness of the other portions of the inner core sheet 34.

  The stator 30 is a laminated iron core including the outer core sheet 32 and the inner core sheet 34 configured as described above. A cylindrical outer core 30a and a columnar inner core 30b are formed by laminating a plurality of outer core sheets 32 and inner core sheets 34 coaxially, and a winding 38 is wound around the iron core 35 of the inner core 30b. Then, the outer core 30a and the inner core 30b are integrally fixed by press-fitting the tab tail portion 34a of the inner core 30b into the fitting portion 32a of the outer core 30a.

  As shown in FIG. 2, the iron core portion 35 located at about 10:30 in the figure is an iron core portion 35a, and the iron core portions 35b, 35c, 35d, 35e, 35f, 35g, 35h, and 35i are sequentially clockwise from this point. And In FIG. 2, the thin portion 37 located at about 11:30 is a thin portion 37a, and the thin portions 37b, 37c, 37d, 37e, 37f, 37g, 37h, and 37i are clockwise approximately every 40 degrees.

In the brushless motor M of this example, the windings 38U1 to 38U3 are wound around the iron core portions 35a to 35c by concentrated winding, respectively, to form the winding 38U. Similarly, the windings 38V1 to 38V3 and the windings 38W1 to 38W3 are wound around the iron cores 35d to 35f and the iron cores 35g to 35i, respectively. A wire 38V and a winding 38W are configured.
However, the windings 38U1, 38U3, 38V1, 38V3, 38W1, 38W3 are wound in the same direction, and the remaining windings 38U2, 38V2, 38W2 are wound in the opposite direction.

In the stator 30 configured as described above, a portion corresponding to the thin portion 37 of the inner core sheet 34 is cut off intermittently in the axial direction. Therefore, the substantial thickness of the portion corresponding to the thin portion 37 is smaller (about half) than the thickness of other portions of the stator 30.
As described above, in the portion corresponding to the thin portion 37, the effective cross-sectional area of the magnetic path through which the magnetic flux flows is reduced, so that the magnetic resistance is increased. Therefore, of the magnetic fluxes generated from the magnets 26 of the rotor 20 and flowing through the stator 30, the leakage fluxes passing through the bridging portions 36 and flowing in the direction of the adjacent magnets 26 are reduced. The effective magnetic flux flowing can be increased. As a result, the output of the brushless motor M of this embodiment is increased.

Here, in the inner core sheet 34 of this example, the iron core portions 35a to 35i are arranged at substantially equal center angle intervals (approximately 40 ° intervals) in the circumferential direction. Thin portions 37a to 37i having a predetermined angular width are formed at substantially the center in the circumferential direction of the bridging portion 36 connecting the spaces.
As shown in FIG. 2, the angle between the center of each of the thin portions 37 a and 37 b in the circumferential direction located at around 11:30 and around 12:30 with respect to the rotation axis center O of the rotor 20 is defined as an angle A. Assuming that angles B, C, D, E, F, G, H, and I are clockwise angles formed by the centers of the adjacent thin portions 37 with respect to the rotation axis center O, the angles A to I are substantially equal. The angle is constant (40 degrees).

  However, the circumferential angular width of each thin portion 37 is set so as not to be constant. That is, the thin portions 37a to 37i are respectively formed in the circumferential directions of about 11 degrees, about 10 degrees, about 12 degrees, about 9 degrees, about 11 degrees, about 8 degrees, about 10 degrees, about 12 degrees, and about 9 degrees. Is formed so as to have an angle width of The average of the angular widths of these thin portions 37 is about 10.2 degrees at the central angle.

FIG. 4 shows a partially enlarged view of FIG. As shown in FIG. 4, assuming that the circumferential widths of the thin portions 37b to 37d are angles b to d, respectively, the angle b is about 10 degrees, the angle c is about 12 degrees, and the angle d is about 9 degrees. Degree. In the present specification, the angle in the circumferential direction of the thin portion 37a sandwiched between the iron core portion 35a and the iron core portion 35b is angle a, and the circumferential angle of the thin portion 37b sandwiched between the iron core portion 35b and the iron core portion 35c. The angle is referred to as an angle b, and hereinafter similarly referred to as angles c to i.
Then, the inner core sheet 34 having the thin portions 37a to 37i formed in this manner is laminated so that the thin portions 37 having the same angular width are located in the axial direction without shifting the phase, thereby forming the inner core 30b. Have been. Note that the effective magnetic flux (or output) of the brushless motor M of the present example is substantially the same as a whole in which each thin portion 37 has a constant angular width of about 10.2 degrees.

In the stator 30 described above, the inner core sheet 34 includes the thin portions 37 having the same angular width. However, the present invention is not limited to this. The inner core sheet 34 is formed so that the angular widths in the circumferential direction of all the thin portions 37 are different. May be. FIG. 5 is a development explanatory view when the inner side surface of the inner core 30b is viewed from the center axis side. In the figure, reference numeral _T 1 through T ₉ are respectively represent the center position in the circumferential direction of the iron core portion 35a~ iron core portion 35i.
In the example of FIG. 5, the angles a to i of the inner core sheets 34 are all different, and are about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, and about 8 degrees, respectively. , About 10 degrees, about 11.5 degrees, and about 9.5 degrees. The average of the angular width of the thin portion 37 is about 10 degrees at the central angle. The inner core 30b is formed by laminating the inner core sheets 34 such that the thin portions 37 having the same angular width are arranged in the axial direction.
Also in the example of FIG. 5, each thin portion 37 is formed such that the center in the circumferential direction coincides with the center between the iron core portions 35 located on both sides thereof (that is, the center of the bridge portion 36). I have.

For one rotation of the rotor, pulsation of cogging torque is generated by the least common multiple of the number of magnet poles and the number of salient poles, and the magnitude of cogging torque is inversely proportional to the number of pulsations. In the brushless motor M of this embodiment, the number of poles of the magnet 26 is set to 8 and the number of iron cores 35 is set to 9, and the number of pulsations is relatively increased per rotation of the rotor 20 (in this example, the number of pulsations is 72), and cogging is performed. The torque is set to be small.
Further, in the brushless motor M of this example, as described above, the plurality of thin portions 37 of the inner core sheet 34 are formed so that the angular width in the circumferential direction is not constant, so that all of the pulsations of the above 72 are performed per rotation. Are not the same change modes, but a plurality of change modes are mixed.
That is, when the angular width of the thin portion 37 is all constant, the pulsation of the cogging torque is concentrated on a single frequency component, but the thin portion 37 has a plurality of angular widths as in this example. In this case, since the magnetic interaction between the magnetic flux received from the magnet 26 and the bridging portion 36 during the operation of the brushless motor M and the rotation angle that exerts the magnetic interaction differ for each bridging portion 36, the pulsation of the cogging torque is plural. Are dispersed in the frequency components of

  Therefore, in the brushless motor M of the present example in which the angular widths of the plurality of thin portions 37 in the circumferential direction are not constant, the conventional brushless motor in which the angular width in the circumferential direction of the thin portions 37 is formed constant. By comparison, the number of pulsations (72) of cogging torque and the average magnitude of cogging torque generated in one rotation of the rotor 20 are similar to those of the conventional one, but a plurality of noises and vibrations occur during operation. Are reduced as a whole as compared with the conventional one.

As described above, in the brushless motor M of the present example, noise and vibration during operation are effectively reduced only by forming the angle width of the thin portion 37 so as not to be constant as compared with the conventional brushless motor. This is preferable because no manufacturing cost is required and no additional work procedure is required.
In addition, in the stator 30 of the present embodiment, the adjacent thin portions 37 are formed so that the angular widths in the circumferential direction are not the same, but the invention is not limited thereto, and at least one of the thin portions 37a to 37i is thin. 37 can be formed so that the circumferential width of the other thin portion 37 is different from the circumferential width of the other thin portion 37.

Further, in the first embodiment, as shown in FIGS. 3 and 5, each inner core sheet 34 is formed by forming the concave portions 36 a to 36 i on one side (upper side in the drawing) of the bridging portion 36 in the axial direction, thereby reducing the thickness. A part 37 is formed. However, the present invention is not limited to this, and the concave portions 36a to 36i may be formed on the other side (lower side in the figure) or both sides of the bridging portion 36 as shown in FIG.
FIG. 6A corresponds to the inner core sheet 34 shown in FIG. Angles a to i are about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees, respectively. Is set to
In the inner core sheet 34 shown in FIG. 6B, the thin portions 37 are formed by forming the concave portions 36a to 36i on both sides in the axial direction of the bridging portion 36, respectively.
In the inner core sheet 34 shown in FIG. 4C, the thin portions 37 are formed by forming the concave portions 36a to 36i on the lower side in the axial direction of the bridging portions 36, respectively.
In the inner core sheet 34 shown in FIG. 4D, the thin portions 37 are formed by forming the concave portions 36a to 36i on the upper and lower sides in the axial direction of the bridging portion 36, respectively. In this example, the concave portions 36a to 36i are formed alternately on the upper side and the lower side in the circumferential direction.
In the inner core sheet 34 shown in FIG. 7E, the thin portions 37 are formed by forming the concave portions 36a to 36i on the upper side, both sides, and the lower side in the axial direction of the bridging portion 36, respectively. . In this example, the concave portions 36a to 36i are formed alternately on the upper side, both sides, and the lower side in the circumferential direction.
In the inner core sheet 34 shown in FIGS. 7B to 7E, the thickness in the axial direction and the angular width in the circumferential direction of the thin portions 37a to 37i are the same as those of the thin portion 37 in FIG. It is formed so as to have the same thickness in the axial direction.
Also, as shown in FIGS. 3D and 3E, the concave portions 36a to 36i do not have to be formed alternately on the upper side, both sides, and the lower side in the circumferential direction to form the thin portions 37a to 37i. The thin portions 37a to 37i may be formed by randomly forming 36i on the upper side, both sides, and lower side in the circumferential direction.

FIGS. 7A and 7B are examples in which the stator 30 shown in FIG. 5 is formed using the three types of inner core sheets 34 shown in FIGS. 6A to 6C.
In the example of FIG. 7A, the inner core sheet 34 of FIG. 6B, the inner core sheet 34 of FIG. 6A, the inner core sheet 34 of FIG. To form an inner core 30b.
In the example of FIG. 7B, the inner core sheet 34 of FIG. 6A, the inner core sheet 34 of FIG. 6B, the inner core sheet 34 of FIG. To form an inner core 30b.

FIG. 8A shows an example in which the stator 30 shown in FIG. 5 is formed using the two types of inner core sheets 34 shown in FIGS. 6A and 6B. In this example, the inner core 30b is formed by sequentially laminating the inner core sheet 34 of FIG. 6A, the inner core sheet 34 of FIG.
FIG. 8B illustrates an example in which the stator 30 illustrated in FIG. 5 is formed using the inner core sheet 34 illustrated in FIG. In this example, the inner core sheet 34 of FIG. 6B is laminated in the axial direction to form the inner core 30b.

As described above, the thin portion 37 of the inner core sheet 34 may be formed by forming the concave portions 36 a to 36 i on any of the upper side, the lower side, and both sides in the axial direction of the bridging portion 36.
Although not described in the embodiments described below, as shown in FIGS. 6A to 6E, the thin portion 37 formed by forming the concave portions 36a to 36i on the upper side, the lower side, and both sides in the axial direction is formed. The present invention also includes a stator 30 formed by appropriately laminating the inner core sheets 34 having the same.

(Example 2)
Next, a second embodiment of the present invention will be described with reference to FIGS. Note that portions common to the first embodiment are denoted by common reference numerals, and redundant description is omitted.
The rotor 20 of the second embodiment is the same as the rotor 20 of the first embodiment, and has eight magnetic poles. Further, the stator 30 of the second embodiment has nine iron core portions 35a to 35i similarly to the stator 30 of the first embodiment, and the iron core portions 35a to 35i have substantially the same central angle in the circumferential direction. They are arranged at intervals (approximately 40 degrees).
However, unlike the thin portion 37 of the stator 30 of the first embodiment, the angular width in the circumferential direction is not formed to be constant, whereas the thin portion 37 of the stator 30 of the second embodiment has a substantially constant angular width (about 10 Degree) is formed.
Further, the thin portion 37 of the first embodiment is formed substantially at the center of the bridge portion 36 in the circumferential direction, but the thin portion 37 of the second embodiment is not at the center of the bridge portion 36 in the circumferential direction but at the center. Are formed at positions displaced in the circumferential direction by a predetermined angle.

That is, in the second embodiment, as in the first embodiment, assuming that the angle formed by the center of the adjacent thin portion 37 with respect to the rotation axis center O is the angle A to the angle I, the angles A to I are respectively about 38 degrees in the central angle. Degrees, about 40 degrees, about 41 degrees, about 40 degrees, about 39 degrees, about 40 degrees, about 42 degrees, about 39 degrees, and about 41 degrees. In short, the thin portions 37a to 37i are formed such that their centers in the circumferential direction are arranged at irregular intervals with respect to the center O of the rotating shaft when viewed from the axial direction of the stator 30. As described above, the circumferential center of the bridging portion 36 and the circumferential center of the thin portion 37 are not all at the same angle, and the predetermined displacement angle has different angles.
Compared to the stator 30 of the first embodiment, the thin portions 37a to 37i are about -1 degree, about +1 degree, about +1 degree, about 0 degree, about 0 degree, about +1 degree, about +1 degree, about +1 degree, respectively. It is displaced in the circumferential direction by -1 degree and about 0 degree. In this specification, the displacement angle is based on a constant circumferential direction, and for example, -1 degree is the same as +359 degrees.

  FIG. 10 is a partially enlarged view of FIG. As shown in FIG. 10, assuming that the circumferential widths of the thin portions 37b to 37e are angles b to e, respectively, the angles b to e are all set to a constant value of about 10 degrees. However, the angles B to D are set to about 40 degrees, about 41 degrees, and about 40 degrees, respectively, so that adjacent angles are not constant.

  The inner core sheet 34 thus formed is laminated so that the thin portions 37 having the same angular width are located in the axial direction without shifting the phase similarly to the first embodiment, thereby forming the inner core 30b. . The effective magnetic flux (or output) of the brushless motor M according to the second embodiment is such that each thin portion 37 has a constant angular width of about 10 degrees as a whole, and the thin portion 37 extends from the center of the bridging portion 36. It is about the same as that formed without displacement.

  Further, in the brushless motor M of the second embodiment, as described above, the thin portions 37 each having a constant angular width are formed at positions displaced from the central portion of the bridge portion 36 by a predetermined angle, respectively. During the operation, the magnetic interaction between the magnetic flux of the magnet 26 and the bridging portion 36 and the rotation angle at which the magnetic interaction occurs differ for each bridging portion 36, so that the pulsation of the cogging torque per rotation is the same as in the first embodiment. Not all are the same change modes, but a plurality of change modes are mixed.

  Therefore, also in the brushless motor M of the second embodiment, the pulsation of the cogging torque is dispersed into a plurality of frequency components, and the pulsation number (72) of the cogging torque generated in one rotation of the rotor 20 as compared with the conventional brushless motor. Although the average magnitude of the cogging torque is similar to that of the related art, the noise and vibration generated during operation are reduced as a whole compared to the related art by being dispersed into a plurality of frequency components.

  In the stator 30 according to the second embodiment, the thin portions 37a to 37i are all formed to have the same angular width. However, the present invention is not limited to this. The stator 30 according to the first embodiment has an unequal angular width. It may be formed.

(Example 3)
Next, a third embodiment of the present invention will be described with reference to FIGS. Note that, like in the second embodiment, common portions are denoted by common reference numerals, and redundant description is omitted.
The rotor 20 of the third embodiment is the same as the rotor 20 of the first embodiment, and has eight magnetic poles. Further, the stator 30 of the third embodiment has nine iron core portions 35a to 35i like the stator 30 of the first embodiment, but unlike the stator 30 of the first embodiment, the iron core portions 35a to 35i are different from the stator 30 of the first embodiment. The iron cores 35i are not arranged at equal intervals in the circumferential direction.

That is, as shown in FIG. 11, the iron core 35b, the iron core 35e, and the iron core 35h are arranged at substantially equal intervals at a central angle of about 120 degrees. Further, the iron core portions 35a and 35c are arranged on both sides of the iron core portion 35b so that the central angles thereof are about 45 degrees. The iron cores 35d and 35f are arranged on both sides of the iron core 35e so that the central angles thereof are about 45 degrees. The iron cores 35g and 35i are arranged on both sides of the iron core 35h so that the central angles thereof are about 45 degrees. As described above, in the stator 30 of the third embodiment, the iron core portions 35 are arranged at unequal pitch.
With this configuration, in the third embodiment, when the center of the N pole of the magnet 26 is disposed on the center line of the iron core 35b in FIG. 11, the magnet 26 is positioned on the center line of the iron cores 35a and 35c. The center of the south pole will be located. This is not limited to the U-phase winding 38U, but also applies to the V-phase and W-phase windings 38V and 38W. The brushless motor M is supplied with the U-phase, V-phase, and W-phase excitation currents, which are 120 degrees out of phase, to the windings 38 of each phase.

  As described above, since the iron cores 35a to 35c and the magnetic poles of the magnet 26 are disposed so as to face each other, the windings 38U1 to 38U3 of the iron cores 35a to 35c are generated. The induced voltages are substantially matched without causing a phase shift, and the conversion loss when converting the exciting current into the rotating magnetic field is suppressed to a small value. The same applies to the iron core portions 35d to 35f and the iron core portions 35g to 35i. Thereby, in the brushless motor M according to the third embodiment, the supplied excitation current is efficiently converted into the rotational torque, and the output is increased.

Further, in the stator 30 according to the third embodiment, the thin portions 37a to 37i formed in the bridging portion 36 connecting the adjacent iron core portions 35 are formed in the circumferential direction similarly to the stator 30 according to the first embodiment. It is formed so that the angular width is not constant.
That is, each of the thin portions 37a to 37i has a circumferential angular width of about 11 degrees, about 10 degrees, about 12 degrees, about 9 degrees, about 11 degrees, about 8 degrees, about 10 degrees, and about 12 degrees. , About 9 degrees in the circumferential direction.

Further, in the stator 30 according to the third embodiment, the thin portions 37a to 37i are not substantially at the center of the bridging portion 36 as in the stator 30 according to the second embodiment, but at positions displaced by a predetermined angle from the center. Is formed.
That is, in FIG. 11, the angles A to I are respectively about 43 degrees, about 37.5 degrees, about 38.5 degrees, about 45 degrees, about 36.5 degrees, about 37.5 degrees, and about 47 degrees in the central angle. Degrees, about 36.5 degrees, and about 38.5 degrees. If not displaced, angles A through I are 45, 37.5, 37.5, 45, 37.5, 37.5, 45, 37.5, and 37. 5 degrees.
Therefore, in the third embodiment, the thin portions 37a to 37i are respectively about -1 degree, about +1 degree, about +1 degree, about 0 degree, about 0 degree, about +1 degree, about +1 degree, about -1 degree, It is displaced in the circumferential direction by about 0 degrees.

  FIG. 12 shows a partially enlarged view of FIG. As shown in FIG. 12, assuming that the circumferential widths of the thin portions 37b to 37d are angles b to d, respectively, the angles b to d are approximately 10 degrees, approximately 12 degrees, and approximately 9 degrees, respectively. Is set. The angles B and C are set to about 37.5 degrees and about 38.5 degrees, respectively, so that adjacent angles are not constant.

As described above, in the brushless motor M of the third embodiment, the angular width of the adjacent thin portion 37 is set so as not to be constant, and the thin portion 37 is displaced by a predetermined angle from the center of the bridge portion 36. It is formed in the position where it was.
With this configuration, during the operation of the brushless motor M, the magnetic interaction between the magnetic flux of the magnet 26 and the bridging portion 36 and the rotation angle at which the magnetic interaction is exerted differ for each bridging portion 36. As in the first embodiment, the pulsation of the cogging torque per one rotation is not all the same, but a plurality of changes are mixed.

Therefore, also in the brushless motor M of the third embodiment, since the pulsation of the cogging torque is more efficiently dispersed to a plurality of frequency components, noise and vibration generated during operation are dispersed to the plurality of frequency components. It is reduced as a whole.
Further, in the brushless motor M according to the third embodiment, the iron core portions 35 are not substantially uniform in the circumferential direction, and the iron core portions 35b, 35e, and 35h are arranged at a center angle of about 120 degrees each other. Are shifted by about 45 degrees (corresponding to the central angle of adjacent magnetic poles of the magnet 26) on both sides. By doing so, the rotating magnetic field generated by the exciting current and the magnetic flux from the magnet 26 can be made to act efficiently, so that the output of the brushless motor M can be increased.

(Example 4)
Next, a fourth embodiment which is a modification of the first embodiment will be described with reference to FIG. In the stator 30 of the fourth embodiment, as in the first embodiment, the thin portions 37 of the inner core sheet 34 all have different angular widths in the circumferential direction. However, in the stator 30 according to the fourth embodiment, unlike the first embodiment, the inner core sheets 34 are stacked out of phase so that the thin portions 37 having the same angular width in the axial direction are not continuous.
More specifically, in this embodiment, each inner core sheet 34 has a circumferential angle width of the thin portion 37 of about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, The angles are set to about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees. The average of the angular width of the thin portion 37 is about 10 degrees at the central angle.
The inner core 30b is formed by sequentially laminating the inner core sheets 34 with a phase shift of 40 degrees so that the thin portions 37 having the same angular width do not continue in the axial direction. That is, for example, the angle a of the thin portion 37a between the iron core portion 35a and the iron core portion 35b is about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees in the axial direction from the top in the figure. The angles are about 8.5 degrees, about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees. Thereafter, the inner core sheet 34 is laminated so that this is repeated in the axial direction.
Here, the arrangement of the thin portions 37 sandwiched between the two iron core portions 35 in the axial direction is referred to as an array of the thin portions 37. In each of the arrays, the thin portions 37 adjacent in the axial direction have an angle in the circumferential direction. They are arranged with different widths.
In this embodiment, in addition to making the circumferential angular widths of the thin portions 37 different from each other in each inner core sheet 34, the inner core sheets 34 are laminated so that the same circumferential angular width is not continuous in the axial direction. Further, noise and vibration during operation of the brushless motor M are further reduced.
In the present embodiment, each thin portion 37 is formed such that the center in the circumferential direction coincides with the center between the iron core portions 35 located on both sides thereof (that is, the center of the bridge portion 36). .
In this embodiment, as in the stator 30 of the third embodiment, the iron cores 35 may be arranged at irregular pitches. The same applies to the following embodiments.

(Example 5)
Next, a fifth embodiment will be described with reference to FIG. In the stator 30 according to the fifth embodiment, in each of the inner core sheets 34, the point that the circumferential widths of the thin portions 37 are all the same and the thin portions 37 having the same angular width in the axial direction are formed so as not to be continuous. This is different from the first embodiment in the point.
More specifically, in the present embodiment, three types of inner core sheets 34 are prepared, and the angular widths of the thin portions 37 in the circumferential direction are about 12 degrees, about 10 degrees, and about 8 degrees. In the uppermost inner core sheet 34 in the figure, the angles a to i are all about 12 degrees, and the second inner core sheet 34 is all about 10 degrees in the angles a to i. 34, the angles a to i are all about 8 degrees, and the inner core 30b is formed by laminating the fourth and subsequent stages so that these are repeated every three stages. Therefore, the thin portions 37 having the same angular width in the circumferential direction are arranged for each of the fixed number of inner core sheets 34.
Not only every three layers, but also four kinds of inner core sheets 34 are prepared and laminated at a repetition cycle of every four steps, five kinds of inner core sheets 34 are prepared and laminated at a repetition cycle of every five steps, or several kinds are made irregular. The inner core 30b may be formed by laminating in an appropriate order.
As described above, in the present embodiment, the inner core 30b is formed by laminating the inner core sheets 34 so that the thin portions 37 having the same angular width are not continuous. That is, the angle a to i of the thin portion 37 in the axial direction from the uppermost stage in the drawing is about 12 degrees, about 10 degrees, about 8 degrees, about 12 degrees, about 10 degrees, about 8 degrees, and so on. The inner core sheet 34 is laminated as described above.
In this embodiment, the inner core sheet 34 is laminated such that the angular width of the thin portion 37 in the circumferential direction is not continuous in the axial direction, thereby reducing noise and vibration during operation of the brushless motor M.
In the present embodiment, each thin portion 37 is formed such that the center in the circumferential direction coincides with the center between the iron core portions 35 located on both sides thereof (that is, the center of the bridge portion 36). .

(Example 6)
Next, a sixth embodiment, which is a modification of the first and second embodiments, will be described with reference to FIG. In the stator 30 according to the sixth embodiment, as in the first embodiment, all the angular widths in the circumferential direction of the thin portions 37 formed on the respective inner core sheets 34 are different. Further, similarly to the second embodiment, each thin portion 37 is formed at a position shifted by a predetermined angle from the center between the iron core portions 35 located on both sides (that is, the center of the bridging portion 36).
More specifically, in this embodiment, each inner core sheet 34 has a circumferential angle width of the thin portion 37 of about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, The angles are set to about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees. The average of the angular width of the thin portion 37 is about 10 degrees at the central angle. The thin portions 37a to 37i are, for example, only about -1 degree, about +1 degree, about +1 degree, about 0 degree, about 0 degree, about +1 degree, about +1 degree, about -1 degree, and about 0 degree, respectively. Displaced in the circumferential direction. In the drawing, the broken line in the direction of the vertical axis indicates the center position of the bridging portion 36. The amount of displacement in the circumferential direction is not limited to this, and may be randomly selected as a whole in the circumferential direction.
The inner core 30b is formed by laminating the inner core sheets 34 without shifting the phase. That is, the inner core sheet 34 is laminated such that the thin portions 37 having the same angular width are continuously arranged in the axial direction. Further, the thin portions 37 having the same displacement angle are arranged continuously in the axial direction.
In this embodiment, in each inner core sheet 34, each thin portion 37 is formed so that all angular widths in the circumferential direction are different, and each thin portion 37 is formed in the circumferential direction from the center of the bridging portion 36. Each is formed at a position displaced by a predetermined angle. As a result, noise and vibration during operation of the brushless motor M are reduced.

(Example 7)
Next, a seventh embodiment which is a modification of the fourth and second embodiments will be described with reference to FIG. In the stator 30 according to the seventh embodiment, similarly to the fourth embodiment, all the angular widths in the circumferential direction of the thin portions 37 formed on each inner core sheet 34 are different, and the thin portions 37 having the same angular width are continuous in the axial direction. It is formed not to be. Further, similarly to the second embodiment, each thin portion 37 is formed at a position shifted by a predetermined angle from the center between the iron core portions 35 located on both sides (that is, the center of the bridging portion 36).
More specifically, in this embodiment, each inner core sheet 34 has a circumferential angle width of the thin portion 37 of about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, The angles are set to about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees. Further, the thin portions 37 having the same angular width are not continuous in the axial direction. Further, the thin portions 37a to 37i are circumferentially shifted by about -1 degree, about +1 degree, about +1 degree, about 0 degree, about 0 degree, about +1 degree, about +1 degree, about -1 degree, and about 0 degree, respectively. Has been displaced. Further, the thin portions 37 having the same displacement angle are arranged continuously in the axial direction.
In this embodiment, in each of the inner core sheets 34, the circumferential angular widths of the thin portions 37 are all different, the angular widths of the thin portions 37 are not continuous in the axial direction, and each thin portion 37 is Are formed at positions displaced from the center by a predetermined angle in the circumferential direction, thereby further reducing noise and vibration during operation of the brushless motor M.

(Example 8)
Next, an eighth embodiment which is a modification of the fifth and second embodiments will be described with reference to FIG. The stator 30 of the eighth embodiment is formed so that the thin portions 37 having the same angular width are not continuous in the axial direction, as in the fifth embodiment. Further, similarly to the second embodiment, each thin portion 37 is formed at a position shifted by a predetermined angle from the center between the iron core portions 35 located on both sides (that is, the center of the bridging portion 36).
More specifically, in the present embodiment, three types of inner core sheets 34 in which the angle widths of the thin portions 37a to 37i of each inner core sheet 34 are about 12 degrees, about 10 degrees, and about 8 degrees, respectively, are sequentially laminated. An inner core 30b is formed. Therefore, the thin portions 37 having the same angular width in the circumferential direction are arranged for each of the fixed number of inner core sheets 34. Further, the thin portions 37a to 37i are circumferentially shifted by about -1 degree, about +1 degree, about +1 degree, about 0 degree, about 0 degree, about +1 degree, about +1 degree, about -1 degree, and about 0 degree, respectively. Has been displaced. Further, the thin portions 37 having the same displacement angle are arranged continuously in the axial direction.
Thus, in this embodiment, the angular width of the thin portion 37 is not continuous in the axial direction, and each thin portion 37 is formed at a position displaced from the center of the bridging portion 36 in the circumferential direction by a predetermined angle. As a result, noise and vibration during operation of the brushless motor M are reduced.

(Example 9)
Next, a ninth embodiment, which is a modification of the second embodiment, will be described with reference to FIG. In the stator 30 according to the ninth embodiment, similarly to the second embodiment, each thin portion 37 is formed at a position shifted by a predetermined angle from the center between the iron core portions 35 located on both sides (that is, the center of the bridge portion 36). I have.
However, in the present embodiment, unlike the second embodiment, the displacement angle is not constant in the axial direction.
More specifically, in the present embodiment, the angular width of each of the thin portions 37 is set to about 8 degrees. The inner core 30b of this embodiment has an inner core sheet 34 in which all the thin portions 37a to 37i are displaced in the circumferential direction by about +2 degrees, and a thin inner portion 37a to 37i in which all the thin portions 37a to 37i are displaced in the circumferential direction by about -2 degrees. The inner core sheet 34 is formed by alternately laminating two types of inner core sheets 34. With such a configuration, the stator 30 is configured such that the thin portion 37 is skewed for each inner core sheet 34. At this time, the skew period is two stages. Therefore, the thin portions 37 having the same displacement angle are arranged in the axial direction for each of the two inner core sheets 34.

Also, as shown in FIG. 18B, five types of inner core sheets 34 (displacement angles: -2 degrees, -1 degree, 0 degrees, +1 degree, +2 degrees) in which the displacement angles of the thin portions 37a to 37i are the same. ) May be used to form the inner core 30b.
That is, the inner core 30b is formed by laminating five types of inner core sheets 34 in which the thin portions 37a to 37i are all displaced in the circumferential direction by about -2 degrees, -1 degree, 0 degrees, +1 degree, and +2 degrees. be able to. At this time, the displacement angles of the thin portion 37 are 0 °, + 1 °, + 2 °, + 1 °, 0 °, −1 °, −2 °, −1 ° so that the thin portion 37 gradually skews in the axial direction. Are laminated in this order. By doing so, the skew cycle of the thin portion 37 can be set long. At this time, the cycle of the skew is eight stages. Therefore, the thin portions 37 having the same displacement angle are arranged in the axial direction for each of the eight inner core sheets 34.
As described above, in the present embodiment, each thin portion 37 is formed at a position displaced from the center of the bridging portion 36 by a predetermined angle in the circumferential direction, and the thin portion 37 is provided between the same iron core portions 35. Since the displacement angle of 37 is not continuous in the axial direction, noise and vibration during operation of the brushless motor M are reduced.

(Example 10)
Next, a tenth embodiment, which is a modification of the ninth embodiment, will be described with reference to FIG. In the present embodiment, although not particularly limited, the stator 30 having six (even number) iron core portions 35 will be described as an example. In the stator 30 of the tenth embodiment, similarly to the ninth embodiment, each thin portion 37 is formed at a position shifted by a predetermined angle from the center between the iron core portions 35 located on both sides (that is, the center of the bridging portion 36). I have.
However, in the present embodiment, unlike the ninth embodiment, in each inner core sheet 34, the circumferential displacement angle of the thin portion 37 is not constant. In this example, in the odd-numbered inner core sheets 34, the displacement angles of the thin portions 37a, 37c, and 37e are −2 degrees, but the displacement angles of the thin portions 37b, 37d, and 37f are +2 degrees. On the other hand, in the inner core sheet 34 of the even-numbered stages, the displacement angle of the thin portions 37a, 37c, and 37e is +2 degrees, but the displacement angle of the thin portions 37b, 37d, and 37f is -2 degrees.
Therefore, when these are alternately stacked, the thin portion 37 is skewed for each inner core sheet 34 between the adjacent iron core portions 35 as shown in FIG. At this time, the skew period is two stages. However, the skew between the thin portions 37 adjacent in the circumferential direction is 180 degrees out of phase.
In the present example, the central angle of the circumferential center of the thin portion 37 adjacent in the circumferential direction is not the same as in the ninth embodiment when viewed in the axial direction, but is periodically widened or narrowed. .

Further, as shown in FIG. 19B, five types of inner core sheets 34 may be stacked. That is, in this example, in the uppermost inner core sheet 34, the displacement angles of the thin portions 37a to 37f are 0 degrees. In the second-stage inner core sheet 34, the displacement angles of the thin portions 37a, 37c, and 37e are +1 degrees, whereas the displacement angles of the thin portions 37b, 37d, and 37f are -1 degrees. In the third-stage inner core sheet 34, the displacement angles of the thin portions 37a, 37c, and 37e are +2 degrees, but the displacement angles of the thin portions 37b, 37d, and 37f are -2 degrees. The fourth inner core sheet 34 is the same as the second inner core sheet 34. The fifth inner core sheet 34 is the same as the uppermost inner core sheet 34. In the sixth-stage inner core sheet 34, the displacement angles of the thin portions 37a, 37c, and 37e are -1 degrees, whereas the displacement angles of the thin portions 37b, 37d, and 37f are +1 degrees. In the seventh stage inner core sheet 34, the displacement angles of the thin portions 37a, 37c, and 37e are −2 degrees, but the displacement angles of the thin portions 37b, 37d, and 37f are +2 degrees. The eighth inner core sheet 34 is the same as the sixth inner core sheet 34. The ninth inner core sheet 34 is the same as the uppermost (and) inner core sheet 34 again. Hereinafter, the layers are stacked so as to be repeated. By doing so, the skew cycle of the thin portion 37 can be set long. At this time, the cycle of the skew is eight stages. In the examples of FIGS. 19A and 19B, thin portions 37 having the same displacement angle are arranged in the axial direction for each of the two and eight inner core sheets 34.
As described above, in the present embodiment, each thin portion 37 is formed at a position displaced from the center of the bridging portion 36 by a predetermined angle in the circumferential direction, and the thin portion 37 is provided between the same iron core portions 35. Since the displacement angle of 37 is not continuous in the axial direction, noise and vibration during operation of the brushless motor M are reduced.

(Example 11)
Next, an eleventh embodiment which is a modification of the first and ninth embodiments will be described with reference to FIG. In the stator 30 according to the eleventh embodiment, as in the first embodiment, all the angular widths in the circumferential direction of the thin portions 37 formed on the respective inner core sheets 34 are different. Similarly to the ninth embodiment, each thin portion 37 is formed at a position displaced from the center of the bridging portion 36 by a predetermined angle, and the thin portions 37 having the same displacement angle are set so as not to be continuous in the axial direction. ing.
More specifically, in this embodiment, each inner core sheet 34 has a circumferential angle width of the thin portion 37 of about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, The angles are set to about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees.
The inner core 30b is formed by using five types of inner core sheets 34 (displacement angles: -2 degrees, -1 degree, 0 degrees, +1 degree, +2 degrees) in which the displacement angles of the thin portions 37a to 37i are the same. ing. The five types of inner core sheets 34 are laminated such that the thin portions 37 having the same displacement angle amount are not continuous. The stator 30 of this example is formed such that the displacement angle of the thin portion 37 periodically changes in the axial direction for each of the eight inner core sheets 34. That is, the skew cycle is eight stages. Therefore, the thin portions 37 having the same displacement angle are arranged in the axial direction for each of the eight inner core sheets 34.
As described above, in the present embodiment, the circumferential widths of the thin portions 37 of the inner core sheets 34 are all different, and each thin portion 37 is displaced by a predetermined angle in the circumferential direction from the center of the bridging portion 36. The brushless motor M is reduced in noise and vibration when the brushless motor M is operated because it is formed at a different position and the displacement angle of the thin portion 37 is not continuous in the axial direction between the same iron core portions 35.

(Example 12)
Next, a twelfth embodiment, which is a modification of the fourth and ninth embodiments, will be described with reference to FIG. In the stator 30 according to the twelfth embodiment, similarly to the fourth embodiment, all the angular widths of the thin portions 37 formed on the inner core sheets 34 in the circumferential direction are different, and the thin portions 37 having the same angular width in the axial direction are also different. The layers are stacked so as not to be continuous. Further, similarly to the ninth embodiment, each thin portion 37 is formed at a position displaced by a predetermined angle from the center of the bridging portion 36, and the same displacement angle amount is not continuous in the inner core sheets 34 laminated in the axial direction. It is set as follows.
More specifically, in this embodiment, each inner core sheet 34 has a circumferential angle width of the thin portion 37 of about 11 degrees, about 10.5 degrees, about 12 degrees, about 9 degrees, about 8.5 degrees, The angles are set to about 8 degrees, about 10 degrees, about 11.5 degrees, and about 9.5 degrees.
The inner core 30b is formed by using five types of inner core sheets 34 (displacement angles: -2 degrees, -1 degree, 0 degrees, +1 degree, +2 degrees) in which the displacement angles of the thin portions 37a to 37i are the same. ing. The five types of inner core sheets 34 are stacked with a phase shift of 40 degrees so that the thin portions 37 having the same angular width are not continuous. By stacking in this manner, in the stator 30 of the present example, the displacement angle of the thin portion 37 periodically changes in the axial direction for each of the eight inner core sheets 34. Therefore, the thin portions 37 having the same displacement angle are arranged in the axial direction for each of the eight inner core sheets 34.
As described above, in the present embodiment, in each inner core sheet 34, all the angular widths in the circumferential direction of the thin portions 37 are different, the thin portions 37 having the same angular width in the axial direction are not continuous, and each thin portion 37 By being formed at a position displaced by a predetermined angle in the circumferential direction from the center of the bridging portion 36, and since the displacement angle of the thin portion 37 is not continuous in the axial direction between the same iron core portions 35, the brushless Noise and vibration during the operation of the motor M are reduced.

(Example 13)
Next, a thirteenth embodiment, which is a modification of the fifth embodiment, will be described with reference to FIG. In the stator 30 of the thirteenth embodiment, as in the fifth embodiment, in each of the inner core sheets 34, all the angular widths of the thin portions 37 in the circumferential direction are the same, and the thin portions 37 having the same angular width in the axial direction are not continuous. Is formed.
Specifically, in the present embodiment, nine types of inner core sheets 34 are prepared, and the angular width of the thin portion 37 in the circumferential direction is about 12 degrees, about 11 degrees, about 10 degrees, about 9 degrees, and about 8 degrees. , About 7 degrees, about 6 degrees, about 5 degrees, and about 4 degrees.
However, unlike the fifth embodiment, these nine types of inner core sheets 34 are formed at positions where each thin portion 37 is displaced from the center of the bridging portion 36 by a predetermined angle in the circumferential direction. Specifically, the thin portion 37 having an angle width of about 12 degrees is about 0 degree in the circumferential direction, the thin portion 37 having an angle width of about 11 degrees is about +0.5 degrees in the circumferential direction, and the angle width is about 10 degrees. The thin portion 37 is approximately +1 degree in the circumferential direction, the thin portion 37 having an angular width of approximately 9 degrees is approximately +1.5 degrees in the circumferential direction, and the thin portion 37 having an angular width of approximately 8 degrees is approximately +2 degrees in the circumferential direction and angle. The thin portion 37 having a width of approximately 7 degrees is approximately +2.5 degrees in the circumferential direction, the thin portion 37 having an angle width of approximately 6 degrees is approximately +3 degrees in the circumferential direction, and the thin portion 37 having an angle width of approximately 5 degrees is circumferential. The thin portion 37 having an angle width of about +3.5 degrees and an angle width of about 4 degrees is formed at a position displaced by about +4 degrees in the circumferential direction.
These nine types of inner core sheets 34 are periodically laminated in this order.
As described above, in this embodiment, the thin portions 37 having the same angular width in the axial direction are not continuous, and each thin portion 37 is formed at a position displaced from the center of the bridging portion 36 in the circumferential direction by a predetermined angle. In addition, since the displacement angle of the thin portion 37 is not continuous in the axial direction between the same iron core portions 35, noise and vibration during operation of the brushless motor M are reduced.

In the above-described embodiment, an example in which the number of magnetic poles is 8 and the number of salient poles is 9 has been described. However, the present invention is not limited to this, and other combinations of the number of magnetic poles and the number of salient poles may be used. It is possible.
Further, in the above-described embodiment, a through hole (not shown) may be provided in a part of the thin portion 37 of each inner core sheet 34 in the circumferential direction and the radial direction to penetrate in the axial direction. By doing so, it is possible to further reduce the leakage magnetic flux that does not contribute to the rotation of the motor.

As described above, the present embodiment has the following effects.
(1) In the stator 30 according to the first embodiment, the thin portion 37a to the thin portion for preventing the leakage magnetic flux to the bridging portion 36 connecting the radially inner side of the iron core portions 35a to 35i arranged radially. A portion 37i is formed, and the thin portions 37a to 37i are formed so that adjacent ones have different angular widths in the circumferential direction.
With this configuration, the brushless motor M of the present embodiment can achieve high output by preventing leakage flux at the bridging portion 36 and can reduce pulsation of cogging torque generated during rotation of the rotor 20. It is possible to reduce noise and vibration as a whole by dispersing a plurality of frequency components without concentrating on one frequency component.

(2) In the stator 30 according to the second embodiment, the thin portions 37a to 37i have substantially the same angular width in the circumferential direction, but the substantially central portion of the bridge portion 36 in the circumferential direction. Instead, it is formed at a position displaced from the center by a predetermined angle in the circumferential direction.
With such a configuration, the brushless motor M of the present example can achieve high output by preventing leakage magnetic flux at the bridging portion 36, and can disperse cogging torque pulsation into a plurality of frequency components. Noise and vibration can be reduced as a whole.

  (3) Further, like the stator 30 according to the third embodiment, the circumferential angle width of the thin portion 37 is made different between adjacent ones, and the center of the bridge portion 36 is not the center but the center. By forming at a position displaced by a predetermined angle in the circumferential direction from, the pulsation of the cogging torque can be more efficiently dispersed to a plurality of frequency components, and noise and vibration during operation of the brushless motor M can be reduced. Becomes possible.

(4) In the bridging portion 36 of the inner core sheet 34 to be laminated, the thin portion 37 can be formed by forming the concave portion 36 on any of the upper side, the lower side, and both sides. By doing so, noise and vibration generated when the brushless motor M operates can be reduced.
(5) As in the case of the stator 30 of the fourth to thirteenth embodiments, the thin portions 37 formed on the inner core sheet 34 are all formed to have different angular widths, and are formed by being displaced by a predetermined angle in the circumferential direction. Conditions such as that the thin portions 37 having the same angular width are not continuously stacked in the axial direction, and that the thin portions 37 having the same displacement angle amount are not continuous in the axial direction are appropriately selected. By setting, it is possible to reduce noise and vibration during operation of the brushless motor M as a whole.

It is sectional drawing of the brushless motor of an Example. FIG. 2 is a cross-sectional view of the stator and the rotor according to the first embodiment. FIG. 2 is a perspective view of the stator core according to the first embodiment. FIG. 3 is a partially enlarged view of the stator according to the first embodiment. FIG. 3 is a development explanatory view of the stator according to the first embodiment. It is a development explanatory view of an inner core sheet. FIG. 3 is a development explanatory view of the stator according to the first embodiment. FIG. 3 is a development explanatory view of the stator according to the first embodiment. FIG. 9 is a cross-sectional view of a stator and a rotor according to a second embodiment. FIG. 7 is a partially enlarged view of a stator according to a second embodiment. FIG. 13 is a sectional view of a stator and a rotor according to a third embodiment. FIG. 13 is a partially enlarged view of a stator according to a third embodiment. FIG. 14 is a development explanatory view of a stator according to a fourth embodiment. FIG. 14 is a development explanatory view of a stator according to a fifth embodiment. FIG. 15 is an explanatory view showing the development of the stator according to the sixth embodiment. FIG. 18 is an explanatory view showing the development of the stator according to the seventh embodiment. FIG. 16 is an explanatory view showing the development of the stator according to the eighth embodiment. FIG. 19 is a development explanatory view of a stator according to a ninth embodiment. It is a development explanatory view of the stator of Example 10. FIG. 34 is a development explanatory view of the stator of the eleventh embodiment. FIG. 34 is a development explanatory view of the stator of the twelfth embodiment. FIG. 34 is a development explanatory view of the stator of the thirteenth embodiment.

Explanation of reference numerals

Reference Signs List 20 rotor, 22 rotating shaft, 24 shaft, 26 magnet, 30 stator, 30a outer core, 30b inner core, 32 outer core sheet, 32a fitting portion, 34 inner core sheet, 34a tab tail portion, 35 iron core portion, 36a to 36i concave portion , 36 bridge portion, 37 thin portion, 38 winding, 40 housing, 41, 42 bearing, M brushless motor, O rotation shaft center, T center position of iron core in circumferential direction

Claims (24)

A cylindrical outer core,
A plurality of iron cores provided on the inner peripheral side of the outer core and projecting radially inward to be wound with windings, and a bridge connecting the radially inner ends of the plurality of iron cores to each other. And an inner core formed by laminating an inner core sheet comprising:
The plurality of bridging portions formed on the inner core sheet have a predetermined width in the circumferential direction of the stator and have a thickness along the axial direction of the stator smaller than other portions of the inner core sheet. A stator, wherein each of the formed thin portions is formed, and at least one of the thin portions has a circumferential width different from that of the other thin portions. A cylindrical outer core,
A plurality of iron cores provided on the inner peripheral side of the outer core and projecting radially inward to be wound with windings, and a bridge connecting the radially inner ends of the plurality of iron cores to each other. And an inner core formed by laminating an inner core sheet comprising:
The plurality of bridging portions formed on the inner core sheet have a predetermined width in the circumferential direction of the stator and have a thickness along the axial direction of the stator smaller than other portions of the inner core sheet. The formed thin portions are respectively formed,
The stator in which the thin portion is formed such that its circumferential center is shifted from the circumferential center of the bridge portion by a predetermined displacement angle in the circumferential direction. A cylindrical outer core,
A plurality of iron cores provided on the inner peripheral side of the outer core and projecting radially inward to be wound with windings, and a bridge connecting the radially inner ends of the plurality of iron cores to each other. And an inner core formed by laminating an inner core sheet comprising:
The plurality of bridging portions formed on the inner core sheet have a predetermined width in the circumferential direction of the stator and have a thickness along the axial direction of the stator smaller than other portions of the inner core sheet. Each of the thin portions is formed, and at least one circumferential width of the thin portions is formed to be different from the other,
The stator in which the thin portion is formed such that a circumferential center thereof is shifted from a circumferential center of the bridge portion by a predetermined displacement angle in a circumferential direction. A cylindrical outer core,
A plurality of iron cores provided on the inner peripheral side of the outer core and projecting radially inward to be wound with windings, and a bridge connecting the radially inner ends of the plurality of iron cores to each other. And an inner core formed by laminating an inner core sheet comprising:
The plurality of bridge portions formed on the inner core sheet have substantially the same width in the circumferential direction of the stator and have a thickness along the axial direction of the stator that is greater than other portions of the inner core sheet. Thin parts formed thinly are formed respectively,
The inner core is formed by laminating a plurality of types of inner core sheets having different circumferential widths of the thin portions so that the circumferential widths of the thin portions adjacent to each other in the axial direction are different from each other. Features stator.   4. The stator according to claim 1, wherein the inner core is formed by laminating each inner core sheet on which thin portions having different circumferential widths are formed. 5.   The inner core is formed by laminating inner core sheets on which thin portions having circumferential widths different from each other are formed such that circumferential widths of the thin portions adjacent in the axial direction are different from each other. The stator according to claim 1. In each of the inner core sheets, the thin portions are formed so that the circumferential widths thereof are different from each other, and the thin portions are formed such that the circumferential center thereof extends in the circumferential direction from the circumferential center of the bridging portion. Formed with a predetermined displacement angle shifted,
The inner core is formed by laminating the inner core sheets such that the circumferential widths of the thin portions adjacent in the axial direction are substantially the same and the displacement angles of the thin portions adjacent in the axial direction are substantially the same. The stator according to claim 1, wherein: In each of the inner core sheets, the thin portions are formed so that the circumferential widths thereof are different from each other, and the thin portions are formed such that the circumferential center thereof extends in the circumferential direction from the circumferential center of the bridging portion. Formed with a predetermined displacement angle shifted,
The inner core is formed by laminating the inner core sheets such that the circumferential widths of the thin portions adjacent in the axial direction are different from each other and the displacement angles of the thin portions adjacent in the axial direction are substantially the same. The stator according to claim 1, wherein:   The stator according to claim 2, wherein the inner core is formed by laminating the inner core sheets such that displacement angles of the thin portions adjacent in the axial direction are different from each other. In each of the inner core sheets, the thin portions are formed so that their circumferential widths are substantially the same, and the thin portions are formed with substantially the same displacement angle,
The inner core is formed by laminating a plurality of types of inner core sheets set with different displacement angles of the thin portions so that the displacement angles of the thin portions adjacent in the axial direction are different from each other. Item 3. The stator according to item 2.   11. The inner core according to claim 10, wherein the inner core is formed by laminating the inner core sheets such that thin portions having substantially the same displacement angle are repeatedly arranged in the axial direction for each of a certain number of the inner core sheets. 12. Stator.   The stator according to claim 10, wherein the inner core is formed by alternately laminating two types of the inner core sheets set with different displacement angles of the thin portion. In each of the inner core sheets, the thin portion is formed such that its circumferential width is substantially the same,
In each of the inner core sheets, the thin portions adjacent to each other in the circumferential direction have substantially the same displacement angle, and the directions of displacement are formed in opposite directions,
The stator according to claim 2, wherein the inner core is formed by laminating the inner core sheets such that displacement angles of the thin portions adjacent in the axial direction are different from each other.   In the inner core, a plurality of types of inner core sheets having different thicknesses of the displacement angles of the thinner portions are repeatedly arranged in the axial direction with a constant number of the thinner portions having substantially the same displacement angle in each of the inner core sheets. The stator according to claim 13, wherein the stator is laminated so as to be formed. In each of the inner core sheets, the thin portions are formed so that their circumferential widths are different from each other, and the thin portions are formed with substantially the same displacement angle,
The inner core is formed by laminating a plurality of types of inner core sheets set with different displacement angles of the thin portions so that the displacement angles of the thin portions adjacent in the axial direction are different from each other. Item 3. The stator according to item 2.   16. The inner core sheet according to claim 15, wherein the inner core sheet is formed by laminating the inner core sheets such that thin portions having substantially the same displacement angle are repeatedly arranged in the axial direction for each of a fixed number of the inner core sheets. Stator.   16. The stator according to claim 15, wherein the inner core is formed by laminating the inner core sheets so that circumferential widths of the thin portions adjacent in the axial direction are substantially the same.   16. The stator according to claim 15, wherein the inner core is formed by laminating the inner core sheets so that circumferential widths of the thin portions adjacent in the axial direction are different from each other. In each of the inner core sheets, the thin portions are formed so that their circumferential widths are substantially the same, and the thin portions are formed with substantially the same displacement angle,
The inner core has a circumferential width and a displacement angle of the thin portion such that the circumferential widths of the thin portions adjacent in the axial direction are different from each other, and the displacement angles of the thin portions adjacent in the axial direction are different from each other. 3. The stator according to claim 2, wherein a plurality of types of inner core sheets set with different values are laminated. In each of the inner core sheets, the thin portion is formed such that its circumferential center is shifted from the circumferential center of the bridging portion by a predetermined displacement angle in the circumferential direction,
The stator according to claim 4, wherein the inner core is formed by laminating the inner core sheets such that displacement angles of the thin portions adjacent in the axial direction are substantially the same.   5. The stator according to claim 1, wherein the plurality of iron cores are formed at unequal intervals in a circumferential direction of the stator. 6.   21. The thinner portion according to claim 1, wherein the inner core sheet is formed with a concave portion on one side, the other side, or both sides in the axial direction of the bridge portion. A stator according to any one of the preceding claims.   The inner core is formed by forming a concave portion on one side in the axial direction of the bridge portion, the inner core sheet in which the thin portion is formed, and forming the concave portions on both axial sides of the bridge portion. The inner core sheet in which the thin portion is formed, and the inner core sheet in which the thin portion is formed by forming a concave portion on the other side in the axial direction of the bridging portion, are laminated in this order. The stator according to any one of claims 1 to 20, wherein A stator according to any one of claims 1 to 23,
A rotor disposed inside the stator and having magnets of different polarities alternately arranged at substantially equal intervals in the circumferential direction of the outer peripheral surface.

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